Science: Technoquest

Q There have been many reports in the press over the last couple of years about devices that produce more energy than is put into them. How do they work?

These devices, called over-unity devices, use water to produce energy. Many people are developing them all over the world, but no one is sure how they work. One company in Russia has even started selling them to the public to use in their heating systems.

They work on the principle of collapsing bubbles. By creating a vortex in a tube, you get water with microbubbles in it. When these collapse they create heat, which is then collected and converted to energy for use in industry or the home. What is so special is that they give out more energy than they take in - something thought to be impossible. One machine in the US which is being investigated by Nasa, gives out between 1.3 and 1.7 times as much energy as it takes in.

Q What does Nicam stand for?

Nicam stands for Near Instantaneous Comprended Audio Multiplex. Nicam broadcasting uses three channels - one for mono and two for digital stereo. "Comprended" describes what happens to the signal: it is compressed at the transmission stage and expanded at the receiving end.

Q What is a column?

A column is a structure formed in the atmosphere by the injection of ejecta into the air in a volcanic eruption.

Q What is a plume?

A plume is a buoyant flow of fluid which, in a volcano, would be volcanic ejecta and hot air.

Q Who invented the miner's head lamp?

The first lighting supported by the head was a candle, which was inserted into a device which could hook onto the miner's hat. The holder could also hook onto beams, coal faces and ladders and was widely used in the early 1800s. These holders were first used by Cornish miners and went over to America during the "Gold Rush" in the 1840s.

The second type of head lamp was an acetylene lamp, which was attached to the cap. The first patent granted to such a cap lamp was given to Rudolph C Kruschke of Duluth, Minnesota on 21 October 1902 (US Patent No 711 871). The lamp was named "The Brilliant Search Light" and was described as an "acetylene gas belt generator and cap burner lamp".

The third type of head lamp was an electric lamp - the type still used today. Developed in about 1910, by 1935 these were more common than any other type of lamp. The first batteries were liquid-powered, making them large and heavy; as a result they were worn around the waist. As battery technology has improved, the battery as well as the lamp itself became supported by the head. However, the inventor does not seem to have patented this system.

The Technoquest website is at http://www.sciencenet.org.uk